Activity ceiling The amount of activity you can do without triggering a later worsening of symptoms.
Personal, and it moves — good seasons raise it, illness and stress lower it. You find it by comparing the days before your crashes with the days before your quiet stretches.
Finding your activity ceiling →
Baseline Your normal-for-you level of symptoms between flares — the reference point a flare is measured against.
Without a baseline, "bad day" has nothing to be bad relative to. Defining yours is the first thing that makes a symptom log readable.
Defining your baseline →
Baseline drift A slow change in your baseline across months, in either direction.
The pattern memory is worst at seeing, because recency quietly rewrites what "normal" used to feel like. It shows up in a log long before it shows up in recollection.
Boom-bust cycle The pattern of overdoing activity on a good day, crashing for the days that follow, resting until symptoms settle, and then overdoing it again. Clinicians sometimes call it the over-activity rest cycle.
On a log it draws a sawtooth. The tell is that crashes disproportionately follow your best days.
Spotting the sawtooth in your log →
Catastrophizing A thought pattern in response to pain with three components: rumination, magnification, and helplessness.
Common and human rather than a character flaw, and it responds to treatment. Naming it while it is happening is genuinely the first step out.
The "is this forever?" spiral →
Chronic pain Pain that persists or recurs for more than three months.
The three-month threshold is a useful convention, not a biological line — nothing changes about the pain on the ninetieth day.
Crash The everyday term for a severe downturn in symptoms following exertion, used especially in ME/CFS and related conditions.
See post-exertional malaise for the clinical version.
Tracking crashes and their causes →
Energy envelope The range of activity a person can sustain without provoking a worsening of symptoms, a framing used mainly in ME/CFS.
The practical cousin of an activity ceiling, with one important difference: you stay inside an envelope rather than testing its edges.
Why you do not probe the limit in ME/CFS →
Flare A temporary worsening of symptoms above your usual baseline, followed by a return toward it. Also called a flare-up.
What counts as one is yours to set. The useful definition is not the strictest — it is the one you can apply the same way on a Tuesday in March and a Sunday in November.
What counts as a flare →
Lag The delay between a trigger and the symptom response it produces.
Lags are why triggers hide. By the time the symptom arrives, its cause is a day or two back and no longer feels connected to it — which is precisely the gap a written log exists to close.
Working out your own lag →
Orthostatic intolerance The early appearance of symptoms — lightheadedness, trouble thinking and concentrating, increased fatigue — brought on by prolonged sitting or standing.
Worth logging as its own kind of exertion. It explains the crashes that otherwise look causeless, where you "did not do anything" except stand at a counter for forty minutes.
Logging upright time →
Pacing Spending activity inside a budget rather than oscillating between doing everything and doing nothing. Also called activity management.
It carries a grim reputation as being told to do less forever. In practice it is closer to the opposite: boom-bust wastes days on crashes and recovery, and pacing reclaims them.
Pacing without the misery →
Pain scale Any instrument for rating pain intensity, most familiarly the 0–10 numeric rating scale used in clinical settings.
Our stance: for daily self-tracking, a coarse scale with a few named steps beats 0–10, because consistency across months matters more than resolution on any one day.
Why fewer steps beats 0–10 →
Post-exertional malaise (PEM) A worsening of symptoms following exertion that was tolerated before the illness — physical, mental, emotional, or upright. Symptoms typically worsen 12 to 48 hours after the activity and can last days or weeks. It is the core symptom of ME/CFS.
The delay is the whole difficulty. Same-day logging cannot see it; you have to read the two days before each crash.
Tracking around the 12–48 hour lag →
Prodrome Early symptoms that arrive before the main episode of an illness or flare begins.
Whatever yours is, it tends to be the same thing every time — which makes it learnable, but only if you are writing down odd symptoms that do not seem to belong to anything.
Learning your own warning signals →
Rolling load Cumulative exertion built up across several days rather than spent in one.
Some crashes have no single cause: no one day did it, but three moderate days stacked. Invisible unless you read multi-day stretches instead of individual entries.
Reading multi-day stretches →
Symptom diary A running record of symptoms alongside the context that might explain them — activities, sleep, medications, and notes. Also called a pain diary or symptom log.
What makes one useful is not completeness. It is consistency, and recording the same few things the same way for long enough that a pattern has room to appear.
What to actually record →
Trigger Something that precedes your flares often enough to be worth acting on.
Note "often enough". A trigger is a statistical claim about your own data, not a cause — and testing one means counting the times it appeared and nothing happened, not just the times it did.
A practical method for finding yours →
Unrated day A day with no entry in your log.
It means unknown — not symptom-free. An honest tool shows the gap rather than drawing a line straight through it, and a month with holes in it is still perfectly good data.
Why gaps do not ruin your data →